Live Load for space above ceiling

[Ben29]

I have a client that is leasing space in a flex building. They want me to design a "Mechanical Equipment Platform" which will be a framed floor above their conference room/bathroom area. It will be framed with metal stud floor joist and metal stud bearing walls.

Per the architect, "It is my understanding that the platform will not carry any equipment loads. The owner only wants the platform space to access the roof above the conference room if maintenance is required in the future."

The architect is not even showing access to this space in his plans. Not even a pull-down stair.

What live load should I use in the design of this space? I would think either 40 psf or 60 psf given the name of the space. But its a real shame that it needs to be that high because this will require us to cut out a portion of the existing slab as needed to install a new wall footing below the new metal stud "Bearing walls". Its just alot of structure that is being installed for something that will never see the design live load.

Thoughts?

 

[driftLimiter]

Is it even allowed to have a floor with no access to it? My gut says there is a high probability that someday someone will want to use this for storage space. 40 - 60 psf really isn't a high live load, I mean 40 psf is residential live load that's about as low as it gets for interior floor space. If you design it for 40 psf at least you can say that it can be reasonably occupied and used for some mech/const. staging.

I don't think you know that it will never see a 40 psf load. Its commercial space I take it, people always trying to adapt the spaces. Smart money designs that space for future adaptability, some bearing walls and foundations never hurt anyone its not that much cost. Will 100% be cheaper than trying to increase the floor live load capacity later.

 

[phamENG]

Get them to name it appropriately. If it's called a "Mechanical Equipment Platform"...somebody will put mechanical equipment on it eventually.

 

[JStephen]

Seems like there's a separate line for catwalks that might be more fitting to the proposed use, but I don't recall if the loading is any lower.

 

[kipfoot]

from ASCE 7, I'd say use your judgement as to whether it's

catwalks for maintenance access: 40 psf
or
storage areas above ceilings: 20 psf

 

[TLHS]

What's under it right now? Is it a slab on grade?

 

[Tomfh]

If it’s a “Mechanical Equipment Platform” I’d be going more like 100psf.

If they can prove it won’t support mechanical services then 40-60 sounds reasonable.

If they’re going to be hauling equipment thru the area and up onto the roof then 20 seems too low.

 

[XR250]

Are you sure you need a strip footing under this? I imagine the slab can take the line load.
You may be over-estimating how much additional structure this will take.

 

[MotorCity]

Regardless of what the space is or is not designed for, I believe IBC requires you to post the live load (but only perhaps above a certain threshold live load??). Posting the live load should eliminate any doubt in the future.